Don Brennan, QMI Agency

OTTAWA - Two key ingredients in the Senators’ recipe for modest success this season were toughness and chemistry.

That’s why there should be no hesitation in re-signing Matt Carkner.

I understand GM Bryan Murray when he says he “can’t bring them all back” when referring to seven pending unrestricted free agents.

He needs to make room for Jakob Silfverberg, maybe Mika Zibanejad, perhaps Mark Stone, and possibly one, if not both, of Patrick Wiercioch and Mark Borowiecki.

He wants to have openings for a veteran, defensive defenceman to replace Filip Kuba and either another free-agent signing or a training camp surprise.

But there also has to be a spot for a 6-foot-4, 230-pound blueliner who happens to be one of the top heavyweights in the league.

A man among so many boys in the dressing room.

A guy coach Paul MacLean scratched from the lineup during the regular season but leaned on in the playoffs, and someone he would have turned to again in Game 7 against the Rangers if Carkner’s knee wasn’t banged up.

A Winchester product who has a lot of fans here and was making only $700,000 this season. His cap hit won’t be an issue.

Carkner has his shortcomings, but he also has a lot of respect, both around the league and on this team. He has an off-ice demeanour that makes him popular with Senators who play a little bigger and braver knowing he has their back.

Carkner re-emphasized he’ll stop at no length to stand up for them by confronting Brian Boyle in Game 2, and the Senators rallied around the beating he administered.

Going forward, the only possible issue could be Carkner’s knee. But even if it will never again be 100%, he’s worth having as a sixth or seventh defencemen on a team that shouldn’t have to rely every night on two rookie rearguards.

Only four other defencemen are expected to return in September — Erik Karlsson, Jared Cowen, Chris Phillips and Sergei Gonchar. That number could be trimmed to three if Murray can somehow unload Gonchar’s $5.5 million salary.

Re-signing Carkner should be a no-brainer, and at the end of the day I expect Murray will see it as such.

Of the six others who are eligible to test the market, Kuba, defenceman Matt Gilroy and backup goalie Alex Auld are gone. If winger Rob Klinkhammer is re-inked, he’ll likely be playing in Binghamton.

Jesse Winchester is certainly worth retaining if he’s over his concussion problems.

That leaves Zenon Konopka.

Like Carkner, Konopka provided plenty of grit and leadership. (Remember when Senators teams would be searching high and low for those qualities)?

Like Carkner, he watched a number of regular-season games from the press box. Like Carkner, he was tapped on the shoulder by MacLean in the playoffs — and his effort in response should have earned him another contract here.

Konopka could barely walk, his back was so bad, but he pleaded to keep playing. He had the best faceoff winning percentage of any centre on the 16 first-round playoff teams, and he helped set up huge goals in Game 2 and Game 5 victories, both at Madison Square Garden.

Like Carkner, he made $700,000 and wants to come back. Konopka, like Carkner, is 31. There are plenty of miles left in his tank. Also, his personality is strong in the dressing room, where it’s known he’ll do anything it takes to win.

There’s a theory the Senators were able to come from behind to win so many games in the third period because they weren’t intimidated — opponents couldn’t push them around when protecting a lead. The presence of Carkner and Konopka was a big part of that.

Perhaps Konopka isn’t as likely to be re-signed as Carkner because the Senators would like to put Zack Smith in his fourth-line role and sign Chris Kelly to centre the third. But then, Kelly can also play wing.

It’s a great thing to have so much promising youth, but it’s also necessary to possess a blend of veterans with character. Should Murray allow Carkner and/or Konopka to slip away, he’ll bring in more toughness — probably, younger players to fill the role.

But Murray would be messing with chemistry by following that path. and the Senators already have a lot of youth. To show the way and protect them, they’re best hanging on to and rewarding two good men who are already here and eager to reach for a pen.